Successful Surgical and Medical Management of a Pararectal Abscess in a Horse.

Pararectal abscesses are life-threatening conditions that can rupture and cause septic peritonitis. The objective of this case report is to describe aggressive treatment of a pararectal abscess to allow a quick return to competitions. A 14-year-old pony was admitted to the Veterinary Teaching Hospital (VTH) of the University of Perugia because of a suspected intra-abdominal mass. Two weeks earlier, it exhibited clinical signs compatible with colic which was treated medically; however, because of the persistence of a firm mass on the right side of the abdomen noted on rectal palpation, the pony was admitted to the VTH. Based on rectal palpation, rectal ultrasound, neutrophilic leukocytosis, hyperfibrinogenemia, and elevated alkaline phosphatase, the diagnosis of a pararectal abscess was made. The horse was treated with ceftiofur IM and MgSO4/paraffin oil via a nasogastric tube. Standing surgical drainage of the abscess with placement of an indwelling drain was performed, followed by daily lavages with rifampicin and acetylcysteine along with Ringer lactate solution with subsequent passive drainage. A bacterial culture revealed the presence of Streptococcus zooepidemicus that was treated with oral rifampicin. Standing laparoscopy revealed adhesions to the rectum. An epidural catheter was placed for repeated delivery of morphine sulfate. The pony was monitored daily by rectal examination, while complete blood count, fibrinogen, serum amyloid A, and abdominal ultrasound (to assess the size of the abscess) were repeated weekly. The pony progressively improved and was discharged one month later, shortly returning to competitions. This report emphasizes the importance of combining medical and surgical treatments for pararectal abscesses.